The present invention relates to an assembly for the distribution of a pharmaceutical solution, contained in multi-dose vial, into single-dose carpules for single use, or the like, and more particularly for dissolving a lyophilized pharmaceutical product contained in such a vial and distributing the pharmaceutical solution obtained. The invention is particularly advantageously applicable in the case of vaccines which are intended to be stored in lyophilized form until they are used and which therefore require separate presentation of the lyophilized active principle and the solvent. It is preferably applicable to pressurized-jet injection (needleless injection).
The invention also relates to sets of single-dose carpules in the form of clusters, to improved plungers for carpules, to an apparatus especially designed for dissolving lyophilized vaccines and for distribution into carpules, as well as to a process for doing this.
For parenteral administration of medicinal substances, and in particular for vaccination, use is being increasingly made of needleless injection apparatuses which deliver the dose in the form of a very thin and very powerful jet. These applications have been developed not only in veterinary medicine but also in human medicine, since the absence of an injection needle makes it possible to use personnel trained in a short time, to speed up the administration procedure and to avoid the bacterial and, above all, viral infections which may occur if the same injection nozzle is used without sterilization between two or more subjects, which is current practice.
The most advanced transcutaneous jet injection apparatuses use single-use carpules equipped with their own nozzle, which nozzle is intended to be the only part in contact with the skin of the patient during the injection, eliminating the risk of cross-infection, given that the carpule and therefore the nozzle is changed on each injection.
However, it has to date only been possible to use this type of apparatus for ready-to-use vaccines, prepackaged in individual doses in single-dose (one-dose) carpules. Such carpules are, for example, known under the brand name Imule.
The problem remains the same in the case of pharmaceutical products which are preserved only in a lyophilized form and which must therefore be redissolved at the time of use. This is particularly true in the case of vaccines, many of which must be preserved in the lyophilized form.
Packaging them therefore makes it necessary to provide a vial of solvent and a vial of lyophilized active product. Use is then made of a large syringe with which the solvent is recovered, and this solvent is then injected into the vial of lyophilized product. Next, after agitation, the pharmaceutical solution ready for use can be taken up with the aid of a number of single-use syringes equal to the number of doses contained in the vial of lyophilized product.
However, it will be recalled that, in practice, further to the risks of cross-infection when the same needle is used without sterilization for treating several subjects, there is also a high risk of contamination during the operations of redissolving the lyophilized products.
Other major drawbacks are the inaccuracy of the doses administered and the fact that it is difficult to make up the intended number of doses from a given vial of vaccine. This is because, even for experienced individuals, it cannot be guaranteed that the intended number of doses will be administered unless an excess of vaccine is provided, which then leads to a higher cost. Note will, in particular, be made of the loss of product during the operation consisting in purging the air contained in the syringe before administration.
The object of the present invention is thus to provide an assembly which makes it possible, in particular, to dissolve lyophilized pharmaceutical products and distribute them into single-dose carpules for single use, or the like, under optimum conditions of safety, in particular sterility, and efficiency, while making it possible to use conventional vials of lyophilized pharmaceutical products.
Another object of the invention is to provide such an assembly which is compact, which is easy to use in complete safety and which is inexpensive and reliable, so as to permit large-scale use under optimal conditions, in particular in countries in which mass treatments or vaccinations need to be carried out.
Yet another object is to provide such an assembly which can at the same time be used simply for distributing a ready-to-use solution into such carpules.